The bug

When using /execute facing or /execute rotated without an executor defined in the command (for example when running a command from a command block) the rotation change is not applied.

Steps to reproduce:

• Create a new world with the Upcoming Creator Features experimental toggle enabled.
• Place down a repeating command block and insert this command:

  /execute rotated 90 0 run particle minecraft:basic_flame_particle ^ ^ ^1
  

→ It still acts as if the y-rotation were set to 0, emitting the particle southward.

• Insert an /execute as into the command like so:

  /execute as @p rotated 90 0 run particle minecraft:basic_flame_particle ^ ^ ^1
  

→ The rotation is now applied and the particle emits westward, despite the rotation conditions having not changed.